1. Field of the Invention
The present invention relates generally to augmented reality systems, and more particularly, to input devices and methods for user interaction with an augmented reality system.
2. Description of the Related Art
Augmented reality is the technology in which a user's view of the real world is enhanced with additional information generated from a computer model, i.e., the virtual. The enhancements may include labels, 3D rendered models, or shading and illumination changes. Augmented reality allows a user to work with and examine the physical world, while receiving additional information about the objects in it. Some target application areas of augmented reality include computer-aided surgery, repair and maintenance, facilities modification and interior design.
In a typical augmented reality system, the view of a real scene is augmented by superimposing computer-generated graphics on this view such that the generated graphics are properly aligned with real-world objects as needed by the application. The graphics are generated from geometric models of both virtual objects and real objects in the environment. In order for the graphics and the real-world objects to align properly, the pose (i.e., position and orientation) and optical properties of the user and virtual cameras must be the same. The position and orientation of the real and virtual objects in some world coordinate system must also be known. The locations of the geometric models and virtual cameras within the augmented environment may be modified by moving its real counterpart. This is accomplished by tracking the location of the real objects and using this information to update the corresponding transformations of the geometric models within the virtual world. This tracking capability may also be used to manipulate purely virtual objects, ones with no real counterpart, and to locate real objects in the environment. Once these capabilities have been brought together, real objects and computer-generated graphics may be blended together, thus augmenting a dynamic real scene with information stored and processed on a computer.
Recent advances in both hardware and software have made it possible to build augmented reality (AR) systems that can run on regular desktop computers with off-the-shelf display and imaging devices. For example, the ARBrowser™ system, developed at Siemens Corporate Research, runs on a 400 MHz Pentium III machine. The system uses infrared video-based tracking technology, also developed at Siemens Corporate Research. This tracking technology considerably reduces the time required for tracking and pose estimation while maintaining the robustness and accuracy of the pose estimation. These advances allow the AR system to run on a regular computer without specialized display hardware at full frame rate, currently 30 frames per second (fps).
As the above-described advances in tracking speed and accuracy helped realize real-time augmentation, user interaction issues have become more visible. To fully realize the potential of AR systems, users need to interact with the systems and conventional methods, such as a keyboard and mouse, have proved to be very cumbersome. More advanced methods of interaction, i.e., speech driven methods, are hard to integrate with AR systems due to their inherent difficulties, such as “training” the speech driven system, and their large processing power requirements, which will hinder the running of the AR system resulting in lower frame rates and additional delays. Most augmented reality systems, currently being used and developed, are lacking easy-to-use, intuitive and effective means of interaction with the user.